A building site manager has been found guilty of manslaughter by gross negligence after a passer-by was killed when three window frames toppled onto her.

Above: Amanda Telfer was killed as she walked along the pavement past a building site

Lawyer Amanda Telfer, 43, was crushed to death when three unsecured window frames, weighing 655kg, toppled over as she walked along the pavement past a construction site in London’s Hanover Square. The incident happened on 30th August 2012.

The window frames – one around 3.2 metres square and two approximately 3.3m x 1.8m – had been delivered the previous day as scheduled but couldn't be fitted immediately due to other delays on site. They were left on the pavement overnight, leaning against the building, almost vertically. No efforts were made to secure them and no barrier placed around them. No checks were made on them when the individual defendants arrived on site the next morning.

As Amanda Telfer walked past, it is believed a door in the building blew open in the wind, hitting the frames and causing them to topple. A worker inside tried to grab them but they fell, crushing Amanda underneath. She died at the scene.

Kelvin Adsett, aged 64 and from Slough, was the on-site project manager for IS Europe Ltd. He was convicted at the Old Bailey yesterday (23rd March 2017) of manslaughter by gross negligence and offences contrary to Section 7a of the Health and Safety at Work Act.

His colleague Damian Lakin-Hall, 50, from Cobham, was found guilty of workplace safety breaches but acquitted of manslaughter. Both men were bailed to appear for sentencing on 5th May 2017.

IS Europe Ltd was convicted of offences under Section 2 and 3 of the Health & Safety at Work Act.

The convictions follow an investigation by the Health & Safety Executive with the Metropolitan Police. Detective Chief Inspector Andrew Chalmers said: "The individuals and company who were convicted in this tragic case had a laissez-faire attitude to health and safety and did not take their obligations seriously.

"Each had a responsibility for the safety of the construction site but failed to deal with a basic task that very obviously then presented a serious hazard.

"Amanda died four-and-a-half years ago and this has been an incredibly long and complex case to bring before the courts with many many hours of enquiries carried out by my team.

"Her death was completely avoidable and it is satisfying for all involved in this case – and especially Amanda's family – that the jury have convicted these people and companies today. Prosecutions such as this are so important in enforcing adherence to health and safety laws. This tragic case proves just why employers and employees should take their obligations to safeguard workers and the public seriously."

Barry and Ann Telfer, Amanda's parents, said following the verdict: "If construction companies and the people who work for them are not held to account for such high levels of negligence and incompetence then none of us is safe walking the streets next to construction sites. The health and safety training being given is totally inadequate if risk of death to passers-by is ignored.”

They added: "We don't want retribution for our loss of Amanda, though we will never recover from it. We want accountability established, responsibility acknowledged. Her death was avoidable. She was killed by half-ton window frames which had been left standing at the side of a busy public pavement unsecured, unbalanced and unattended with no safety barriers round them. The risk to passers-by is obvious. Yet the risk was ignored and our daughter, a bright, beautiful woman with so much to live for, so much she wanted to do with her life, was killed."